Filter element

ABSTRACT

A filter device having a filter housing ( 1 ) and at least one filter element ( 13 ) that can be received in the filter housing ( 1 ) and that has an inner fluid space ( 71 ), which is limited by a filter medium ( 17 ), through which the fluid to be cleaned can flow, and which separates the inner fluid space ( 71 ) from an exterior fluid space ( 11 ) located in the filter housing ( 1 ), wherein the filter housing ( 1 ) has a fluid inlet ( 7 ) and a fluid outlet for cleaned fluid, characterized in that a fluid guide device ( 9 ) is connected downstream to the fluid inlet ( 7 ), which can be retrofitted such that it optionally forms a flow path between the fluid inlet ( 7 ) and the exterior fluid space ( 11 ), or between the fluid inlet ( 7 ) and the inner fluid space ( 71 ) disposed in the filter element ( 13 ).

The invention relates to a filter device having a filter housing and at least one filter element which can be held in the filter housing and which has an inner fluid space which is bordered by a filter medium through which a fluid which is to be cleaned can flow and which separates the inner fluid space from an outer fluid space which is located in the filter housing, the filter housing having a fluid inlet and a fluid outlet for the cleaned fluid.

Filter devices of this type are generally known in different embodiments and are used in the most varied fluid systems, especially in installations with hydraulic systems. Since as a result of the many possible applications of these filter devices they can be produced in very large numbers, a design which can be economically produced for these filter devices is sought.

Accordingly, the object of the invention is to make available a filter device whose design enables matching to different possible operating modes so that the same filter device can accommodate different applications.

This object is achieved according to the invention by a filter device which has the features of claim 1 in its entirety.

Accordingly, one particularity of the invention consists in that there is the possibility of retrofitting which enables operation of the same filter device, depending on the application-specific requirements, with a filter element through which fluid flows from the exterior to the interior in the filtration process, or with a filter element in which the filtration process takes place such that flow takes place through the filter element from the interior to the exterior.

This enables more versatile applications, since, depending on the pressure level, the volumetric flow and other operating parameters, it should be preferred that in the filtration process flow takes place through the filter element from the exterior to the interior or with flow from the interior to the exterior. With a standardized design, as a result of which the desired economical production is enabled, different requirements can thus be satisfied. Moreover, the cost for warehousing and logistics is reduced due to the standardized design.

The arrangement can be made such that on the fluid guide device there are two set-up sites, of which one set-up site is assigned to the outer fluid space and the second set-up site is assigned to the inner fluid space. The process of retrofitting is made simple and reliable by the very unique assignment.

In advantageous embodiments each set-up site has at least one fluid passage channel, preferably several fluid passage channels, which can be blocked optionally for retrofitting of the fluid guide device. The retrofitting process therefore consists simply in the measure of blocking the fluid passage channels of the first set-up site or the fluid passage channels of the second set-up site.

Advantageously, the arrangement can be made such that the filter housing defines a main axis and that the fluid passage channels of the first set-up site are located at a greater distance from the main axis than the fluid passage channels of the second set-up site. Thus, the mouths of the channels for the filtration process, which takes place in the filter element from the exterior to the interior, are located in the outer wall region of the filter housing so that the filter element is exposed to the flow directly on its exterior, while the fluid passage channels of the second set-up site discharge in the region which is nearer the main axis and which is adjacent to the inner fluid space of the filter element.

The filter device according to the invention preferably has a circularly cylindrical filter element in which the filter medium adjoins a fluid-permeable support tube and the filter element can be held in the filter housing such that the support tube extends concentrically to the main axis. Filter elements of this design are widely used in the pertinent technology.

Preferably, the fluid guide device is mounted in the filter housing between an inlet part, which has the fluid inlet and which borders the housing cover, and a filtration part, which forms the outer fluid space and which is axially offset to the inlet part, preferably in the filtration part an element receiver for the filter element being made such that the filter element is located directly adjacent to the fluid guide device with that end on which the inner fluid space is accessible.

In especially advantageous embodiments, the arrangement there can be made such that the fluid guide device has an adapter plate which is penetrated by the fluid passage channels and which forms on the peripheral side a seal between the inlet part and filtration part of the filter housing and which has a coaxial socket which projects into the filtration part and which forms both the element receiver for the filter element as well as a flow path which leads into the inner fluid space of the filter element. This results in an especially compact design in which the adapter plate in a double function forms the element receiver of the filter element, and according to the selected equipment as the fluid guide device makes available the desired flow paths.

Preferably, in this connection the fluid passage channels of the first set-up site are located on the adapter plate on a circular line which is concentric to the main axis, with a radius that is chosen such that the fluid passage channels form flow paths to the exterior of the filter element.

In this configuration, the fluid passage channels of the second set-up site can also be located on the adapter plate on a circular line which is concentric to the main axis, the radius for this circular line being chosen such that the fluid passage channels form flow paths into the interior of the socket piece which is used as the element receiver.

In especially advantageous embodiments the fluid passage channels of the fluid guide device are made as a seat for the bypass valves which are pretensioned into the blocking position and which can be optionally inserted therein. For outfitting or retrofitting by selective blocking of the fluid passage channels of the first or second set-up site, in this instance by installing bypass valves at the same time the filter device is protected against an excess pressure difference which may be present on the filter medium.

The process of outfitting or retrofitting is made especially simple and convenient when the bypass valves are formed by valve inserts which can be inserted as a premounted functional unit, including a spring-loaded closing part and valve seat, into selected fluid passage channels.

Depending on the selected mode of operation, preferably there are different filter elements. When, according to the outfitting of the fluid guide device, the filtration process takes place such that flow takes place through the filter element from the exterior to the interior, preferably there is a filter element with a support tube which borders the inner fluid space and is surrounded on the exterior by the filter medium. Conversely, when flow takes place through the filter element from the interior to the exterior, preferably there is a filter element with a support tube which is nearest the outer fluid space and is provided on its interior with the filter medium.

The invention is detailed below using one embodiment shown in the drawings.

FIG. 1 shows a shortened, slightly schematically simplified longitudinal section of the embodiment of the filter device according to the invention, the operating state being shown in which flow takes place through the filter element from the exterior to the interior in the filtration process;

FIG. 2 shows a cross section of the embodiment according to cutting line II-II from FIG. 1;

FIG. 3 shows a longitudinal section corresponding to FIG. 1, however, the operating state being shown in which flow takes place through the filter element from the interior to the exterior in the filtration process;

FIG. 4 shows a cross section of the embodiment according to cutting line IV-IV from FIG. 3;

FIG. 5 shows a perspective oblique view of the fluid guide device of the embodiment which is made as an adapter plate, enlarged compared to FIGS. 1 to 4;

FIG. 6 shows a cutaway, truncated perspective of the end section of the embodiment which contains the fluid guide device;

FIG. 7 shows a perspective of a bypass valve insert of the embodiment of the filter device, on a scale approximately twice that of a practical embodiment, and

FIGS. 8 and 9 show individual perspectives of the movable closing part and of the valve seat of the valve insert from FIG. 7.

The device according to the invention has a filter housing 1 in the form of a circularly cylindrical metallic tube body produced by extrusion. On the end shown at the top in FIG. 1 the filter housing 1 is sealed by a housing cover 3 in the form of an aluminum diecasting. The interior of the cover 3 is connected to an inlet part 5 into which the fluid to be cleaned can flow by way of an inlet opening 7. The inlet part 5 is separated from the filtration part 11 in which a filter element 13 is housed by a fluid guide device which is formed by an adapter plate 9. It is a filter element of generally conventional design with a fluid-permeable, circularly cylindrical support tube 15 and a filter medium 17 which adjoins it and which is likewise of conventional type, the filter fineness being matched to the respective application. As FIG. 1 shows, the filter element 13 is held in the filter housing 1 such that the support tube 15 runs concentrically to the main axis 19 of the filter housing 1.

Within the filter housing 1 a protective screen 21 is connected downstream from the filter element 13 such that the fluid which has been cleaned by the filter element 13 travels into the interior of the protective screen 21 by way of an inlet opening 23. After the screened medium 25 passes through the protective screen, the cleaned fluid leaves the filter housing 1 by way of a fluid outlet which is not shown. The protective screen 21 is connected by cementing to the bottom cover 27 which forms the housing termination and on which there is a pressure holding valve 29 that is pretensioned into the closed position.

Details on the adapter plate 9 which is used as a fluid guide device are shown especially clearly in FIG. 5. The adapter plate 9 has a round plate part 31 with an annular groove 33 which is located on the outer peripheral side and in which an O-ring 35 is held, see FIGS. 1, 3 and 6, which seals the adapter plate 9 on the interior wall of the filter housing 1 so that the adapter plate 9 forms a separating element between the inlet part 5 and the filtration part 11. On the collar 37, which projects axially from the plate part 31, to form fluid passage channels, lying on an exterior circular line there are five outer openings 39, and lying on a circular annular line which lies farther to the interior, five inner openings 41, in FIG. 5 of the inner openings 41 only four openings being visible. To attach the adapter plate 9 to the housing cover 3, there is a central peg 43 which projects axially from the collar 37 and on which on the end side a star body with radially running arms 45 (FIG. 5) is molded. As FIGS. 1, 3, and 6 show, the ends of the arms 45 are connected to the housing cover 3 by way of a snap ring 47 which sits in the annular groove of the housing cover.

On the side opposite the peg 43, the adapter plate 9 forms a flanged socket 49 which projects axially, coaxially to the main axis 19, and, which with its beveled exterior 51, forms an element receiver for the filter element 13 which on its end cap 53 has an edge enclosure 55 which can be slipped onto the socket 49, an O-ring 57 forming a seal.

As mentioned, the adapter plate 9 which is used as the fluid guide device can be outfitted or retrofitted such that in the filtration process flow takes place through the filter element 13 either from the exterior to the interior or from the interior to the exterior. FIGS. 1 and 2 show the state in which flow takes place through the filter element 13 from the exterior to the interior. While FIG. 5 shows the adapter plate 9 in a state which has not been outfitted, none of the openings 39 and 41 being equipped with a blocking element, the adapter plate 9 in the operating state from FIGS. 1 and 2 is outfitted such that the openings 39 which belong to the first set-up site are cleared and thus form free fluid passage channels 59 (FIG. 1), these fluid passage channels 59, as can likewise be recognized from FIG. 1, forming flow paths in the filtration part 11 which lead to the exterior of the filter element 13. The openings 41 of the adapter plate 9 which belong to the inner set-up site are blocked by valve inserts 61, of which one is shown separately enlarged in FIG. 7. They are bypass valves with a spring-loaded closing body 65 which is movably guided in a cage 63 and which interacts with a valve seat 67, see FIGS. 7 to 9. On the exterior of the valve seat 67 there is a quarter-turn fastener guide 68 by means of which the valve insert 61 which has been inserted into the opening 39 or 41 can be secured by engaging a safety projection 69 (FIG. 5). FIG. 2 clearly shows that the inner openings 41 of the adapter plate 9 are equipped with valve inserts 61, while the outer openings 39 are open.

In this operating mode a filter element 13 is used in which the support tube 15 is inside and borders the inner fluid space 71 of the filter element 13, the support tube 15 being surrounded on the outer peripheral side by the filter medium 17. In this instance, the filter element 13 has a bottom cover 73, on whose central opening it has an edge enclosure 75 which corresponds to the edge enclosure 55 and into which the input part 79 of the protective screen 21 extends with interposition of an O-ring 77, so that the cleaned fluid travels into the protective screen 21 by way of the opening 23 located thereon. The input part 79 of the protective screen 21 is located on a cover part 83 which is sealed relative to the filter housing 1 by means of an O-ring 81 and which together with the edge enclosure 75 forms an element receiver between the filter element 13 and the protective screen 21.

FIGS. 3 and 4 shows the operating state in which the adapter plate 9 is retrofitted such that the openings 39 which belong to the outer set-up site are equipped with valve inserts 61, while the openings 41 which belong to the inner set-up site are free in order to form fluid passage channels 59 which lead into the interior of the socket 49 and thus into the inner fluid space 71 of the filter element 13. As FIGS. 3 and 6 likewise show, in this connection a filter element 13 is used in which the support tube 15 is located on the exterior and on its interior is provided with the filter medium 17. The fluid which has been cleaned as it passes from the interior to the exterior travels by way of the opening 23 to the protective screen 21. As FIG. 3 clearly shows, in this instance the lower bottom cover 73 of the filter element 13 is continuous, so that it closes the inner fluid space 71. A depression 85 in the bottom cover 73 in interaction with the input part 79 of the protective screen 21 forms the lower centering of the filter element 13. 

1. A filter device having a filter housing (1) and at least one filter element (13) which can be held in the filter housing (1) and which has an inner fluid space (71) which is bordered by a filter medium (17) through which a fluid which is to be cleaned can flow and which separates the inner fluid space (71) from an outer fluid space (11) which is located in the filter housing (1), the filter housing (1) having a fluid inlet (7) and a fluid outlet for the cleaned fluid, characterized in that a fluid guide device (9) is connected downstream from the fluid inlet (7) and can be retrofitted such that it optionally forms a flow path between the fluid inlet (7) and the outer fluid space (11) or between the fluid inlet (7) and the inner fluid space (71) which is located in the filter element (13).
 2. The filter device according to claim 1, characterized in that on the fluid guide device (9) there are two set-up sites (39 and 41), of which one set-up site (39) is assigned to the outer fluid space (11) and the second set-up site (41) is assigned to the inner fluid space (71).
 3. The filter device according to claim 1, characterized in that each set-up site has at least one fluid passage channel (59) which can be blocked optionally for retrofitting of the fluid guide device (9).
 4. The filter device according to claim 3, characterized in that the filter housing (1) defines a main axis (19) and that the fluid passage channels (59) of the first set-up site (39) are located at a greater distance from the main axis (19) than the fluid passage channels (59) of the second set-up site (41).
 5. The filter device according to claim 4, characterized in that there is a circularly cylindrical filter element (13) with a filter medium (17) which adjoins a fluid-permeable support tube (15), and the filter element (13) can be held in the filter housing (1) such that the support tube (15) extends concentrically to the main axis (19).
 6. The filter device according to claim 5, characterized in that the fluid guide device (9) is located in the filter housing (1) between an inlet part (5) which has the fluid inlet (7) and which borders the housing cover (3), and a filtration part (11) which forms the outer fluid space and which is axially offset to the inlet part.
 7. The filter device according to claim 6, characterized in that the fluid guide device has an adapter plate (9) which is penetrated by the fluid passage channels (59), which forms on the peripheral side a seal (35) between the inlet part (5) and filtration part (11) of the filter housing (1) and which has a coaxial socket (49) which projects into the filtration part (11) as the element receiver for the filter element (13) and for forming a flow path into its inner fluid space (71).
 8. The filter device according to claim 7, characterized in that the fluid passage channels (59) of the first set-up site (39) are located on the adapter plate (9) on a circular line which is concentric to the main axis (19), with a radius which is chosen such that the fluid passage channels (59) form flow paths to the exterior of the filter element (13).
 9. The filter device according to claim 8, characterized in that the fluid passage channels (59) of the second set-up site (41) are located on the adapter plate (9) on a circular line which is concentric to the main axis (19), whose radius is chosen such that the fluid passage channels (59) form flow paths into the interior of the socket (49) which is used as the element receiver.
 10. The filter device according to claim 3, characterized in that the fluid passage channels (59) of the fluid guide device (9) are made as a seat for the bypass valves (61) which are pretensioned into the blocking position and which can be optionally inserted therein.
 11. The filter device according to claim 10, characterized in that the bypass valves are formed by valve inserts (61) which can be inserted as a premounted functional unit, including a spring-loaded closing part (65) and valve seat (67), into selected fluid passage channels (59).
 12. The filter device according to claim 1, characterized in that when the fluid guide device (9) is outfitted such that it forms a flow path to the outer fluid space (11) there is a filter element (13) with a support tube (15) which borders the inner fluid space (71) and which is surrounded on the exterior by the filter medium (17).
 13. The filter device according to claim 1, characterized in that when the fluid guide device (9) is outfitted such that it forms a flow path to the inner fluid space (71) there is a filter element (13) with a support tube (15) which is nearest the outer fluid space (11) and which is provided on its interior with a filter medium (17). 